Low intensity long duration training on the treadmill is history. Research shows that high intensity interval training will give you much better results in terms of post workout caloric expenditure. H. I. I. T. (high intensity interval training) is a method to do short intensive and very productive cardio workouts.
You may burn fewer calories during the workout because it usually lasts between 10-30 minutes but your body will be burning more calories for hours after the workout. The main point of the cardio is to is to burn more calories than you put in. Although I recommend that the caloric deficit should be from the output not on the input. It means you have to use proper exercise strategies to increase your burning capabilities rather than allowing your body to starve by not eating enough nutrients. You can’t build the house without nails, wood, shingles, drywall, bricks, etc even if you were to try really hard right? The same applies to your body. You can’t build the muscles needed to burn fat without all the necessary nutrients. After all, you need only 6 different things. Proteins, carbohydrates, fats, vitamins, minerals, water. All these mentioned nutrients must come from a healthy source. You are what you eat. If you want to get a six pack you really have only two options. You either do it all the way through or don’t bother. It’s not easy to have a six pack but it’s not impossible. All it takes is little discipline and a will to get it.